Electric service outlet



NOV. 16, '1948. F H SEALSv 2,454,221

ELECTRIC SERVICE OUTLET Filed Feb. 11, 1946 f ferrara/yam.

Patented Nov. 16, 1948 UNITED STATES PATENT ,()FFICE ELECTRIC `SERVICE OUTLET `Fred H. Seals, Warner Robins,` Ga. Atpiieatidn February 11, 1946, seriaiNo. 646,929

' 2 claims; i (ci. 173-330) I I This invention relates to an electric service outlet and has for its object the provision of a receptacle and a plug, both of new and novel construction, adapted to inter-engage to prevent accidental separating of the partsV by pulling on the service cord or from other causes.

It is another object of the invention to provide' With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the construction and arrangement of parts Without departing from the spirit of the invention as claimed.

In the accompanying drawing the preferred form of the invention has been shown.

In said drawing h Figure 1 is a front elevation of the receptacle member of the device, said receptacle beingof the duplex type and having the cam removed from one socket, the other cam being shown in normal position.v

Figure 2 is an enlarged section through the plug and receptacle portionsvtaken on the line 2./-2 Fig. 3.

Figure 3 is a section on line 3-3 Fig. 2.

Referring to the iigures by characters of reference I designates the casing or box portion of the service outlet which can be of the duplex type as shown or can contain one, two or more sockets. In Figure 1 the two units have been indicated at 2 and 3 and are identical. Each unit includes a cylindrical inner casing or lining 4 provided with a cylindrical socket 5 open at its outer end flush with the outer face of the casing or box I but closed at its inner end. This casing or lining is formed with opposed recesses 6 opening into the socket 5 and each recess is proportioned to receive a beveled contact element 'l carried by a stem 8 which is slidably mounted in the Wall of the lining and is electrically connected as at 9 to one of the terminals I0 of the service outlet receptacle. Preferably, the opposed faces of the contact elements 1 are respectively formed with obliquely disposed or beveled upper portions, and with angular recesses in their lower portions, this construction resulting, as best shown in Figure 2, in the provision of opposed beveled projections 1'. I

Coiled springs II mounted in the recesses 6 and bearing against the contacts I serve to hold the contacts normally pressed out of the recesses 6 as shown for example in Figure 3.

Mounted for rotation in the inner casing or lining 4 is 1an elongated cam or socket member I3 provided with a deep plug receiving recess which can be elliptical in cross-sectional contour or any other suitable `,cross-section conguration other than circular. h

,The outer surface of the wall of cam I3 has diametrically opposed portions reduced in thickness annularly so` that opposed arcuate grooves I5 thus are provided which are of varying depth, each groove being deepest at one end where it penetrates or opens into the socket I4 where the socket is of greatest diameter and as indicated at I6. Thus when the cam I3 is rotated in one direction, the contact elements 'I are thrust backwardly from the openings I6 into the recesses 6. In Figure 3 the contact elements 'I have been shown extending into the openings I5 and it will be noted that during the radial' displacement of these contact elements by rotation of the plug I3 in the direction indicated'by the arrow in Figure 3v said contact elements will ultimately berengaged by seats Il provided at those ends of the grooves I5 remote from the openings I6. This latter position is the normal position of the parts` so that any person reaching into the open end of the Asocket I4 cannot touch the radially displaced contact elements 1 which normally are bearing against the seats I'I.

The plug employed as a part of the invention comprises a. member I8 elliptical in cross-sectional contour and proportioned for insertion into the socketvl4. This member has opposed contacts I9 each having a transversely disposed beveled groove I9' formed in its outer face, for

locking engagementwith the beveled projections 'I' on the contact elements 1. The contacts I9 are located in those portions of the surface of the member I8 which are furthest apart. They are also positioned at such points on the plug that, when the plug is inserted into the socket I4 the contacts I9 will be directly back of the openings IB in the cam I3.

Conducting strips 20 are seated in the plug or insertable element I8 and those end portions thereof remote from the contacts I9 are connected to the terminals of a cord 2| as shown at 22.

A cap 23 can house the terminals of the vcord and also the exposed end portions of conductors 2U to which the cord is attached.

It is to be understood of course that cap 23, insertable member i 8, cam I 3 and casing or lining 4 can all be formed of suitable insulating material.

As before stated the cam I3 is normally positioned with the Contact elements 1 pressed against the seats il at which time the cam i3 is substantially atright angles; to the position shown;l in: Figure 3:" `When it is desired toma-kea connection, the plug, which is oval in cross-section in the form illustrated, is inserted into the socket? I4 until the contacts i9 are ybrought; into'theopena. ings I6. Cam i3 is then rotated in a clock-Wise direction or in a direction opposite-tofthatfindiecated by the arrow in Figure Thus theseats ,I1 will be withdrawn from the contact'elements Tand these elements will gradually be pressed inwardly by their springs H until the openings IE are brought to positions .betweenthe contact rele,- ments-whereupon, said elements' will bewthrust into locking engagementwith the contactsl IS-,as f shown in Figure 2. Consequently an` electrical connection visfestablished,between thev cordy 2| kand the connections 9.. As the parts l and lilinterlock, as shown in Figure 2 while Contact is being maintained,.the plug cannot be withdrawn until after it and the cam i3 are rotated to displace thecontact elements 'l radially toward. or into. the recesses 6..

What is! claimed is:

l. An electrical service outlet and plug including. a cylindrical receptacle, opposed beveledcontact elements slidably mounted inthe wall thereof, yielding means on the contactelements normally urging them toward each other, aA lcylindricalv socket'member rotatable in the receptacle, the socket member having opposedI transversely disposed arcuate cam grooves in its side wall in which the contact elements are received and having a non-circular socket extended inwardly from its outer end, the grooves each being deepest at 'kone end'and communicating at saidends'with.

the socket at opposite points in thel same plane along the vside Wall of' thesocket, means at the respective otheri ends of the grooves adapted to engage rthe contact elements when` the, socket; member is in one extreme position, a plugy formed correspondingly to the socket for insertion thereinto, and opposed contacts mounted in the side` Wall ofthe plugand projecting into said deepest. ends of the grooves, the contacts on the plug being transverselyA grooved `for locking engagement with the contact elements on the receptacle, the socket member being rotatable from said extreme position with the plug inserted, to position the receptacle contact elements at the deepest ends of the cam grooves and thereby bring the plug contacts into locking engagement with said elements.

2. An electrical service outlet and plug including a cylindrical receptacle, opposed contact elementshaving'beveled proi e'ctionsv formed on their opposed-faces, "slidably mountedfin thewall of the receptacle, yielding means on the contact ele- -ments normally urging them toward each other, a-,cylindricalrsocket member rotatable in the receptacle, the socket member having opposed transverselydisposed arcuate cam grooves, varying in deptnfromend to end of each groove, formed in its side wall in which said contact elements,v are received, the socket member having a non-circular` socket extended inwardly from its outer end,` the grooves being each deepest at one end and communicating, at saidV ends withthe.

socket at Vopposite pointsin the same plane along the side wall. of the. socket, said` grooves. having seats. at their respective other ends wherein the contact elements are pressingly engaged when the socket,.member is inA oneV extreme position, a plugnon-circularin cross-section` insertible into thefsocket, andv opposed contacts mounted in the` sidewall of the plug .and projecting into said deepestendsoithe grooves, said contacts having transverse groovesrformed'in their outer faces fo'rlocking engagement with the beveled, projections on the contactv elements, the socket member being rotatable, from said extreme position withthe plug inserted, to positionthe receptacle e contact/elements at the deepest ends of the cam grooves Yand 'thereby bring the plug contacts into locking engagement with saidelements.

` FRED H.` SEALS.

VREFERENCES CITED The following references are of reccrcl'inv the` file of` this patent: 

